Optimize performance-critical algorithms by using branch prediction hints to guide the CPU. Add `UNLIKELY` macros for error conditions, boundary checks, or exceptional cases that rarely evaluate to true, and `LIKELY` for common execution paths. This helps the CPU's branch predictor make better decisions, reducing pipeline stalls and improving execution speed in hot loops and frequently called functions. Example: ```cpp // Less optimized: if (number_num < lower_num || number_num > upper_num) { // Handle out-of-range case } // Optimized with branch prediction: if (UNLIKELY(number_num < lower_num || number_num > upper_num)) { // Handle out-of-range case } ``` This technique is especially important in performance-critical algorithms where the same conditional is evaluated repeatedly and the outcome is predictable in most cases.